This invention relates to a glass cutter including a plurality of cutting discs supported circularly and rotatably between a support plate and a circular cover plate firmly connected thereto, of which cutting discs always one is in readiness for cutting, the casing of the cutting discs defined by the support plate and the cover plate being retained exchangeable in an elongated recess at the head of the glass cutter and the support plate being formed multi-edged at the perimeter.
Such devices are known from German patent specifications No. 1,063,769 and No. 1,237,274.
In one of the prior art glass cutters the casing of the cutting discs is guided rotatable in the recess at the head of the glass cutter and the retaining of the casing in the recess is effected by means of a clamp plate capable of being screwed to the head of the glass cutter, said clamp plate having bent-off portions as the two longitudinal edges thereof, with which it engages at two faces parallel to one another of the plate of the casing facing it. By an engagement of the clamp plate at edge faces of the plate of the casing facing it, a proper and unmovable seating of the cutting disc respectively advanced into the working position is insured. Such glass cutters, have essential disadvantages, however. The shifting of a cutting disc into the working position is complicated and time-consuming because on the one hand for doing so the casing of the cutting discs and the clamp plate must be aligned relative to one another, which is rendered difficult by the movability of the two parts. On the other hand, the clamp plate prior to each shifting of any new cutting disc into the working position must previously be released and subsequently screwed to the head of the glass cutter again. The arrangement of the clamp plate furthermore results in an increase of the production cost of such glass cutters. Finally, such glass cutters are prone to the disadvantages that the stand-by cutting discs are subject to contamination with a glass cutter taken into use by residue of putty or the like, which possibly has as a result a jamming of the cutting discs on their shafts.
A glass cutter having two cutting discs opposing each other is also already known, the cutting discs being supported in a casing made integrally of a flexible material, the casing having two guides by means of which the casing is capable of being pushed onto the bifurcated head of the glass cutter. After wearing of the cutting disc positioned in the working position, the casing on the head of the glass cutter is re-applied, thereby the second cutting disc being in readiness for a cutting operation. Since the casing as a result of its production of flexible material assumes a clamp seat on the bifurcated ends of the head of the glass cutter, no additional clamp or screw elements are required for retaining the casing on the head. Such glass cutters, however, are able to be equipped with two cutting discs only, and this has proven to be a disadvantage in practice, and similarly, the stand-by cutting disc is subject to contamination. Furthermore, a proper supporting of the shafts of the cutting discs in the casing is not possible because of the production of the casing of flexible material, because the shaft of the cutting disc disposed in the working position upon performing a cutting operation is urged into the material as a result of the pressure thereby occurring. The result thereof is a displacement of the cutting disc from the working position, so that no proper cut is able to be performed with the cutting disc any more. In order to counteract this deficiency, the shafts of the cutting discs have been supported in holes of a metallic plate in such glass cutters, in order to prevent a displacement of the shafts in this way. A non-displaceable supporting of the shafts, however, results in a not immaterial cost increase of such glass cutters.